U.S. patent number 4,871,466 [Application Number 07/108,611] was granted by the patent office on 1989-10-03 for novel collectors and processes for making and using same.
This patent grant is currently assigned to American Cyanamid Company. Invention is credited to D. R. Nagaraj, Samuel S. Wang.
United States Patent |
4,871,466 |
Wang , et al. |
October 3, 1989 |
Novel collectors and processes for making and using same
Abstract
A method for the production of alkyl or alkaryl hydroxamic acids
and/or salts wherein a C.sub.8 -C.sub.22 alcohol is employed with
water as the solvent is disclosed as well as the resultant salt
and/or acid solutions per se and their use in the flotation of
non-sulfide minerals, preferably clay.
Inventors: |
Wang; Samuel S. (Cheshire,
CT), Nagaraj; D. R. (Stamford, CT) |
Assignee: |
American Cyanamid Company
(Stamford, CT)
|
Family
ID: |
22323151 |
Appl.
No.: |
07/108,611 |
Filed: |
October 15, 1987 |
Current U.S.
Class: |
252/61; 209/166;
562/621 |
Current CPC
Class: |
B03D
1/01 (20130101); B03D 1/018 (20130101); C09C
1/42 (20130101); B03D 1/002 (20130101); C01P
2006/60 (20130101); B03D 2201/02 (20130101); B03D
2203/04 (20130101) |
Current International
Class: |
B03D
1/01 (20060101); B03D 1/004 (20060101); B03D
1/018 (20060101); C09C 1/40 (20060101); C09C
1/42 (20060101); B03D 001/02 () |
Field of
Search: |
;209/166,167 ;252/61
;260/5.5H,404 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
"Flotation of Oxizized Copper Minerals by the Aroxanic Acids"
Darilov-Obogocchchemie rud vol. 20 #30, 1975..
|
Primary Examiner: Lacey; David L.
Assistant Examiner: Lithgow; Thomas M.
Attorney, Agent or Firm: Van Riet; Frank M.
Claims
We claim:
1. A composition of matter comprising a mixture of water, a
C.sub.10 -C.sub.22 alcohol, a fatty hydroxamic acid salt, of 8-22
carbon atoms and an alkali metal sulfate.
2. A composition according to claim 1 wherein said alcohol is decyl
alcohol.
3. A composition according to claim 1 wherein said alcohol is
dodecyl alcohol.
4. A composition according to claim 1 wherein a cationic or
non-ionic surfactant is also contained in the composition.
5. A composition according to claim 1 in emulsion form.
6. A composition according to claim 5 wherein said emulsion is a
microemulsion.
7. A composition of matter consisting of a C.sub.8 -C.sub.22
alcohol solution of fatty hydroxamic acid of 6-22 carbon atoms.
8. A composition according to claim 7 wherein said alcohol is decyl
alcohol.
9. A composition of matter consisting of a C.sub.8-22 alcohol
solution of fatty hydroxamic acid of 6-22 carbon atoms and a
cationic or non-ionic surfactant.
Description
BACKGROUND OF THE INVENTION
Alkyl or alkaryl hydroxamic acids and their salts are well-known
collectors for the froth flotation of oxide minerals. Soviet
workers have found a variety of applications for such alkyl
hydroxamic acids. A recent review summarizes the flotation
application of alkyl hydroxamic acids (Pradip and Fuerstenau,
"Mineral Flotation with Hydroxamate Collectors", in "Reagents in
the Minerals Industry", Ed. M. J. Jones and R. Oblatt, Inst. Min.
Met., London, 1984, pp. 161-168). Hydroxamic acids have been used
for the flotation of metals or minerals such as pyrochlore (Nb,
Ta), fluorite, huebnerite, wolframite, cassiterite, muscovite,
phosphorite, hematite, pyrolusite, rhodonite, chrysocolla,
malachite, barite, calcite, and rare-earths. They are generally
more powerful and more selective then conventional fatty acids,
fatty amines, petroleum sulfonates and alkyl sulfates. However, the
commercially employed methods of making alkyl or alkaryl hydroxamic
acid or its salts are tedious, and unsafe from the point of view of
industrial production. For example, Organic Synthesis, Vol. II,
page 67 sets forth a procedure for making potassium alkyl
hydroxamate wherein a methanol solution of KOH (56 gm in 140 cc of
methanol) and another of NH.sub.2 OH HCl (41.7 gm in 240 cc of
methanol) are combined. The KCl byproduct is filtered off. To the
filtrate is added 56.1 gm of a mixed liquid of methyl
caprylate/caprate. After standing 24 hours, the product crystals
(50 gm, or 67% yield) are filtered off. A major drawback of this
method is the use of a large amount of methanol which is toxic and
flammable. Another drawback is the use of potassium hydroxide which
is more expensive than sodium hydroxide. Furthermore, the
filtration of methanolic reaction mixture on an industrial scale is
obviously not desirable in terms of safety. Finally, the yields are
quite low.
Hartlage (U.S. Pat. No. 3,922,872, Jan. 20, 1976) claims an
improved method of making fatty hydroxamates. Dimethylamine is used
to effect the reaction between hydroxylamine sulfate and the methyl
ester of a fatty acid in an anhydrous lower alcohol slurry. The
free hydroxamic acids formed are neutralized with dimethylamine or
an alkali metal base to yield, after filtering and drying, the
ammonium or alkali metal salt precipitate. The procedure given,
however, still employs flammable lower alcohols, i.e., methanol,
ethanol or isopropanol. Furthermore, because of the heterogeneous
nature of the reaction, the reaction rate is very slow, e.g., 15
hours in methanol and 5 days in isopropyl alcohol and filtration of
the final hydroxamate product is still necessary. In an operation
when methanol, a toxic flammable liquid, is employed, a hazardous
environment is created. Finally reported yields are only in the
75-76% range.
Various Russian workers have reported methods for making alkyl
hydroxamic acids and/or their salts in aqueous alkaline media.
Sodium alkyl hydroxamates were made by reacting the methyl ester of
a C.sub.7-9 carboxylic acid with an aqueous solution of
hydroxylamine sulfate and NaOH at a molar ratio of 1:1.22:2.2 and a
temperature of 55.degree. C. or below (Gorlovski, et. al. Vses.
Soveshch. po Sintetich. Zhirozamenitelyam, Poverkhnostnoaktivn,
Veschestvam i Moyushchim Sredstvam, 3rd, Sb., Shebekino, 1965,
297-9 Chem. Abst. 66, 4983h, 1967). A yield of only 72-78% of the
free C.sub.7-9 hydroxamic acid was reported by Shchukina et. al.
(Khim. Prom., Moscow, 1970, 49(3) 220) by reacting one mole of the
methyl ester, 1.45 mole hydroxylamine sulfate, 7.39-7.82 moles NaOH
for two hours at 20.degree.-25.degree. C. and one hour at
55.degree.-60.degree. C., followed by acidification to pH 4-5 at
temperatures below 40.degree. C. Again, in Sin. Primen. Novykh
Poverkh. Veshchestv, 1973, 123-31 reported in C.A. 80, 1974,
95199K, Shchukina et al report a simple lab method for the
production of a reagent designated as IM-50 from C.sub.7-9 esters.
In a Russian Patent (U.S.S.R. No. 390,074, July 11, 1973 Chem.
Abst. 79, 115162C (1973)) and also in an article (Zh. Prikl, Khim,
(Leningrad) 1972 45(8), 1895-7, Chem. Abstract 78, 29193m 1973),
Russian workers reported improved yields with the use of 3-5% of an
anionic emulsifier in an alkaline aqueous medium. The authors
reported that the use of an anionic surfactant such as sodium
lauryl sulfate (3-5% based on the weight of the methyl ester), gave
an improved yield of 61.2% for valerihydroxamic acid and 89% for
caprihydroxamic acid. To obtain the yields claimed, however, a 40
molar % excess of hydroxylamine hydrochloride or sulfate was
required. Furthermore, both the sodium salts and the free
hydroxamic acids recovered are solids which are difficult to handle
and process.
In another Russian patent (U.S.S.R. No. 513,970, May 15, 1976,
Chem. Abst. 85, 66277g, 1976) a solution of mixed free C.sub.8-11
hydroxamic acids was obtained in hydrocarbons. This was achieved by
treating the sodium alkylhydroxmates with a mineral acid in the
presence of 100-250 weight percent of a hydrocarbon containing less
than 20% polar organic components (e.g., higher alcohols or
esters). The aqueous layer containing NaCl or Na.sub.2 SO.sub.4 was
discarded as effluent.
Finally, U.S. Pat. No. 4,629,556 has recently issued wherein
various colored impurities are removed from kaolin clays utilizing
alkyl, aryl or alkylaryl hydroxamates as collectors. The
hydroxamates are disclosed as having been produced by reacting free
hydroxylamine with the methyl ester of an organic acid of
appropriate hydrocarbon chain length and configuration in a
non-aqueous medium such as methanol much in the same manner as
taught in the above-mentioned articles.
While these reports certainly represent advancement of the art,
there are still many drawbacks regarding industrial production. On
a large scale of production, for example, the aqueous effluent can
be substantial and can pose a serious problem for disposal.
Furthermore, in order to obtain a product in liquid form, the
alkali metal alkyl hydroxamates must be acidified to the free
hydroxamic acids. This acidification is an additional step and
causes a substantial increase in processing and handling time and
costs. The use of anionic surfactants as taught by the Russians
also causes a foaming problem during manufacture.
SUMMARY OF THE INVENTION
It has now been found that useful alkali metal alkyl hydroxamates
can be produced by reacting the methyl or ethyl ester of a fatty
acid having 6-22 carbon atoms with a hydroxylamine salt and an
alkali metal hydroxide in the presence of a water/C.sub.8 -C.sub.22
alcohol mixture, preferably in the presence of a non-ionic or
cationic surfactant. This procedure results in the formation of a
liquid solution of the hydroxamate which can be used as such in the
froth flotation of non-sulfide minerals such as kaolin clays or
neutralized to form a liquid alcohol solution of the acid which may
also be so utilized. The instant process of producing the alkali
metal alkyl hydroxamate salts and acids eliminates the need for
hazardous and expensive recovery steps such as filtration; it is
relatively rapid, i.e., the reaction is complete in 3-5 hours; and
it results in extremely high conversions, i.e., 85-95%, in the
absence of foaming. When a surfactant is used, the instant process
requires lesser amounts thereof than shown in the art.
Furthermore, when utilized in the froth flotation of non-sulfide
minerals, the alcohol solutions of the hydroxamates and hydroxamic
acids are significantly more effective than prior art compositions
such as IM-50.
DESCRIPTION OF THE INVENTION INCLUDING PREFERRED EMBODIMENTS
As discussed briefly above, the instant invention resides in a
method for the production of a salt of a fatty hydroxamic acid or
the fatty hydroxamic acid per se by reacting a methyl or ethyl
ester of a fatty acid having 6-22 carbon atoms, preferably at least
8 carbon atoms, with a hydroxylamine salt and an alkali metal
hydroxide in the presence of water, a C.sub.8 -C.sub.22 alcohol,
preferably an alcohol of at least 10 carbon atoms. The reaction
proceeds according to the equation: ##STR1## wherein R is a C.sub.6
-C.sub.22 alkyl, an aryl (C.sub.6 -C.sub.10) or an alkaryl (C.sub.7
-C.sub.14) group, M is an alkali metal and R.sup.1 is methyl or
ethyl.
Useful acid esters include the methyl and ethyl esters of such
carboxylic acids as caproic acid (C.sub.6), enanthic acid
(C.sub.7), caprylic acid (C.sub.8), pelargonic acid (C.sub.9),
caproic acid (C.sub.10), undecanoic (C.sub.11), lauric (C.sub.12),
tridecanoic (C.sub.13), myristic (C.sub.14), pentadecanoic acid
(C.sub.15), palmitic acid (C.sub.16), margaric acid (C.sub.17),
stearic acid (C.sub.18) and the like. Oleic acid (C.sub.18),
benzoic acid, ethyl benzoic acid, salicylic acid, .alpha.-and
.beta.-naphthoic acid, cyclohexyl carboxylic acid, cyclopentyl
carboxylic acid etc. are additional examples. Ethyl esters of above
carboxylic acids require a higher reaction temperature than the
methyl esters.
Hydroxylamine salts such as the sulfate or hydrochloride etc., can
be used. Suitable alkali metal hydroxides include NaOH, KOH etc.
Amines such as ammonia, dimethylamine etc. can be used in place of
the hydroxides.
As mentioned above, a non-ionic or cationic surfactant is also
preferably used. Exemplary surfactants include non-ionic
surfactants such as alkyl polyethyleneoxy compounds represented by
the formula:
wherein R is C.sub.8 -C.sub.18 alkyl, EO is ethyleneoxy and n is a
number from 1 to 10. Additional non-ionic surfactants include the
reaction products of ethylene oxide and higher alkylene oxide with
active hydrogen compounds such as phenols, alcohols, carboxylic
acids and amines, e.g., alkylphenoxyethyleneoxy ethanols. Suitable
cationic surfactants are those such as alkyl ammonium or quaternary
ammonium salts, e.g., tetraalkyl ammonium chloride or bromide,
dodecyl ammonium hydrochloride, dodecyl trimethyl quaternary
ammonium chloride and the like, and ethoxylated fatty amines. Other
suitable surfactants are described in McCutcheon's book of
detergents and emulsifiers. Also included in the aforementioned
surfactants are oligomeric and polymerizable surfactants described
at pages 319-322 of Blackley, Emulsion Polymerization Theory and
Practice, John Wiley and Sons (1975). Examples of such oligomers
include ammonium and alkali metal salts of functionalized oligomers
sold by Uniroyal Chemical under the trade name "Polywet" and
copolymers of acrylonitrile and acrylic acid having molecular
weights less than 2000 which are prepared in the presence of chain
terminating agents such as n-octyl mercaptan. Examples of
polymerizable surfactants include sodium salts of 9- and
10-(acrylylamido)stearic acid and the like. The effective amounts
of the surfactant range from about 0.5 to 3%, by weight, of the
alkyl ester, preferably about 1.0%-2.0%, by weight, same basis.
The higher alkyl alcohols are the C.sub.8 -C.sub.22 alcohols,
preferably C.sub.10 -C.sub.18 alcohols. They can be linear or
branched. Examples include octyl alcohol, nonyl alcohol, decyl
alcohol, undecyl alcohol, dodecyl alcohol, tridedecyl alcohol,
tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol,
heptadecyl alcohol, stearic alcohol and the like. These alcohols
may be used individually or as mixtures. The amount needed to
effect a clear liquid varies according to the alcohol used, the
hydroxamate to be made and the amount of water present. Based on
quasi-elastic light scattering experiments, the clear liquids
produced in the process of the invention were found, in reality, to
be in a clear microemulsion form. Their stability is, therefore, a
equilibrium balance between all of the components present. A
generally useful guideline is 75-175 parts of alcohol per 100 parts
of alkyl ester. For decyl alcohol, for example, the weight range
can be 90 parts to 150 parts per hundred parts of the alkyl ester,
preferably 115 to 138 parts. The concentration of the aqueous
solution of hydroxylamine salt may vary from about about 15 to 35%,
preferably from about 25-30%, by weight. The calculated amount of
alkali used should be at least sufficient to both liberate the free
hydroxylamine from its salts and to neutralize the free hydroxamic
acid, although excess amounts (5-15%) may be used. The molar ratio
of hydroxylamine salt to the ester should range from about 1:1 to
1.10:1.0. Excess amounts of hydroxylamine salt greater than 10% can
be used but are not necessary and no beneficial result has been
observed using such excess amounts.
The reaction temperature can range from about 15.degree. to
55.degree. C., preferably from about 25.degree. to 35.degree.
C.
Sufficient water is used to dissolve the hydroxylamine salt. The
amount of water used generally depends upon the concentration of
the hydroxylamine salt solution. Water in the final hydroxamate
salt product can vary from about 30-50%.
The instant invention is also directed to the novel compositions
produced by the above-described process. These compositions
comprise, if no neutralization of the product is conducted, a
water/alcohol solution, the alcohol containing 8-22 carbon atoms,
of the fatty hydroxamic acid salt, an alkali metal sulfate and
preferably include a cationic or non-ionic surfactant. The solution
will contain from about 10% to about 30% of the acid salt, from
about 5% to about 10% of the sulfate, from about 0.0% to about 0.6%
of the surfactant and water as indicated above. Minor or trace
amounts of other ingredients which in no way modify or alter the
final product may also be present.
When the above product is neutralized by the addition of acid
whereby two phases are formed, the aqueous phase is removed such as
by decantation or as described in U.S. Pat. No. 3,933,872,
incorporated herein by reference. The organic phase results in the
second novel composition of the present invention comprising a
C.sub.8 -C.sub.22 alcohol solution of the fatty hydroxamic acid and
preferably the cationic or non-ionic surfactant. The acid content
ranges from about 30% to about 70% and the surfactant ranges from
about 0.0% to about 1.0%.
The above-described compositions are useful in the frother
flotation of non-sulfide mineral ores such as those mentioned above
and including copper ores, iron ores, rare and rare earth metal
ores and, more particularly, in the beneficiation of clays.
Useful flotation methods are those well-known and established to
those skilled in the art. In general, the methods comprise,
firstly, the step of grinding of the ore to provide liberation of
mineral values and ore particle size suitable for flotation.
Secondly, the ground ore pulp is pH-adjusted, and conditioned with
pre-selected and prescribed reagents such as collectors, frothers,
modifiers, and dispersants. With some ores, the as-mined feed
material is already finely divided and, therefore, no additional
grinding is involved. Examples are glass sands, clays, tailings
etc.
In the case of clays beneficiation for example, substantially no
grinding of the as-mined feed is required since the average
particle size is of the order of a few microns. The major
impurities in kaolin clays are anatase (TiO.sub.2) and complex iron
minerals. These impurities impart color to the clay and decrease
its brightness, thus making the clay unsuitable for many of its
applications where purity and brightness are absolutely essential.
Conventionally, the removal of such impurities is accomplished by a
variety of methods, an important one being flotation using tall oil
fatty acid.
In the froth flotation for beneficiating clay wherein the clay is
slurried in an aqueous medium, conditioned with an effective amount
of a dispersing agent and collector and floated, the instant
invention comprises employing, as the collector, the novel
compositions above, i.e., the hydroxamic acid/alcohol solution or
the hydroxamic acid salt/water/alcohol solution in quantities
ranging from about 0.1 to about 18.0 pounds per ton of ore,
preferably 0.5-6 pounds per ton. The novel process of the present
invention results in the recovery of clays in high yields, of low
TiO.sub.2 content and increased brightness.
As a first step in carrying out such a process, the clay to be
purified is blunged in water at an appropriate solids concentration
as described in U.S. Pat. No. 4,629,556, incorporated herein by
reference. A relatively high pulp density, in the range of 35-70%
solids, by weight, is preferred since the interparticle scrubbing
action in such pulps helps liberate colored impurities from the
surfaces of the clay particles.
Following conventional practice, a suitable dispersant, such as
sodium silicate, polyacrylate, or polyphosphate, is added during
blunging in an amount, e.g., 1-20 lb. per ton of dry solids,
sufficient to produce a well-dispersed clay slip. An alkali, such
as ammonium hydroxide, is also added as needed to produce a pH
above 6 and preferably is the range of 8-10.5. The hydroxamate
collector, in accordance with the invention, is then added to the
dispersed clay under conditions, i.e., proper agitation speed,
optimum pulp density, and adequate temperature, which permit
reaction between the collector and the colored impurities of the
clay in a relatively short time, generally not longer than 5-10
minutes.
When the clay has been conditioned after the addition of collector,
it is transferred to a flotation cell and is usually diluted to a
pulp density preferably in the range of about 15-45% solids, by
weight. The operation of the froth flotation machine is conducted
in conventional fashion. After an appropriate period of operation,
during which the titaniferous impurities are removed with the foam,
the clay suspension left in the flotation cell can be leached for
the removal of residual iron oxides, filtered, and dried in
conventional fashion.
The following examples are set forth for purposes of illustration
only and are not to be construed as limitations on the present
invention except as set forth in the appended claims. All parts and
percentages are by weight unless otherwise specified.
EXAMPLE 1
In a suitable three-neck reaction vessel, equipped with a
condenser, a mechanically-driven stirrer and a thermometer, 180.8
parts of hydroxylamine sulfate are dissolved in 448 parts of water.
475 Parts of commercial decyl alcohol (contains 95%
trimethyl-1-heptanols and 5% other homologous primary alcohols),
7.4 parts of a 50% dioctyl/decyl dimethyl ammonium chloride
surfactant, and 337.2 parts of methyl caprylate/caprate are
introduced. With stirring, the reaction mixture is cooled to
10.degree.-15.degree. C. with an ice/water bath. Sodium hydroxide
(336 parts of 50% NaOH) is added slowly through an addition funnel.
The temperature is kept at 15.degree.-20.degree. C. throughout the
addition. After the caustic addition, the temperature is allowed to
rise to 25.degree. C. and the reaction is continued or 2-3 hours at
25.degree.-30.degree. C. The reaction is complete when the IR
spectrum of the reaction mixture shows no trace of the ester band
(1175 cm.sup.-1). The clear liquid, by UV analysis (FeCl.sub. 3
method), gives a hydroxamate content of 20.3% vs. theoretical
21.5%. This represents a 94.4% conversion of the ester into the
sodium hydroxamate salt. The total weight of the liquid is 1,775
parts or a 99.5% recovery of the total charge and is composed of a
capryl/capra hydroxamic acid sodium salt, sodium sulfate and
dioctyl/decyl dimethylammonium chloride micro emulsion in decyl
alcohol and water.
EXAMPLE II
The preparation of Example 1 is repeated with the exception of
replacing the cationic surfactant with 4.0 parts of a non-ionic
surfactant, an ethoxylated nonylphenol (EO=9.5). The emulsion
product is a clear liquid having a 19.0% hydroximate content or 87%
conversion.
EXAMPLE III
Example I is again repeated except that no surfactant is used. The
liquid product is slightly hazy and, on standing, about 5%, by
volume, of an aqueous layer separates on the bottom. Assay gives an
87% conversion to the hydroxamate.
EXAMPLE IV
Example I is again repeated. To the final clear liquid are added
365 parts of 27% hydrochloric acid. Two solution phases form and
are separated. The upper organic layer containing the free
hydroxamic acid (892 parts) is found, by analysis, to contain 34%
free hydroxamic acid vs. 38% theoretical or 89.5% conversion. It is
a solution of the capryl/capra hydroxamic acid in decyl alcohol.
The product is compatible with tall oil fatty acids.
EXAMPLES V-VII
Example I is again repeated except that the decyl alcohol is
replaced with (V) isooctyl alcohol, (VI) dodecyl alcohol and (VII)
a 1:1 mixture of iso-octyl and dodecyl alcohol. The conversions to
the hydroxamates are all excellent (89-92%). The product of Example
VII remains liquid on standing at room temperature while those of
Example V and Example VI solidify. Addition of 10% water to (V)
gives a clear liquid product. The product of Example VI (400 parts)
is neutralized with 81 parts of a 30% sulfuric acid (pH 7.0), and
the organic layer is separated from the aqueous layer (196 parts
with 35% hydroxamic acid content or 90% conversion). The liquid
product is again found to be compatible with tall oil fatty
acid.
EXAMPLES VIII-IX
Replacement of the decyl alcohol of Example I, all else remaining
equal, with (VIII) stearic alcohol or (IX) hexadecyl alcohol
results in the production of substantially identically appearing
compositions.
EXAMPLES X-XIII
The procedure of Example I is again followed except that the methyl
caprylate/caprate is replaced by an equivalent amount of (X) methyl
stearate; (XI) ethyl oleate; (XII) methyl palmitate or (XIII)
methyl naphthoate. Similar results are achieved.
EXAMPLE XIV
386 Parts of fresh wet kaolin clay (equivalent to about 300 parts
dry solids) are blunged at 65% solids for 5 minutes in a commercial
blender with water, ammonium hydroxide (to give a final pH of
9.0-9.5), and 0.48 part of sodium silicate. A prescribed amount of
collector of the present invention (or other collector for
comparative purposes) is then added to the well dispersed clay
slurry and conditioned in the blender for an additional 5 minutes.
The conditioned pulp is then transferred to a 1.2 l flotation cell,
diluted with water to about 25% solids, agitated at 1000 rpm and
floated with carefully regulated air flow (in the range 0.1 to 1.5
/l min. of air) for up to 15 minutes.
The floated product containing mostly the anatase impurity and the
unfloated, cell product containing the clean and bright clay values
are filtered, dried and assayed for TiO.sub.2 and Fe. The results
are set forth in Table I, below:
TABLE I
__________________________________________________________________________
Removal of Anatase Impurities from Kaolin Clays Clay Product Dosage
Bright- % Clay Ex. # Collector Kg/t % TiO.sub.2 ness Yield
__________________________________________________________________________
A Tall oil fatty acid* 2 0.6 85.9 49*** B C.sub.8 carboxylic acid*
2 1.22 83.4 65*** C C.sub.12 carboxylic acid 2 1.01 84.5 80 D
Mixture of C.sub.1 & C.sub.18 carboxylic acids* (1.5 + 0.5)**
0.70 85.5 70 E.sup.x C.sub.8 -C.sub.10 hydroxamate (Methanol
Method) 1 0.22 87.1 78 F.sup.y C.sub.8 -C.sub.10 hydroxamate
(Methanol Method) 1 0.25 88.8 86 G.sup.z Sodium octyl hydroxamates
(Soviet Teachings) 1 0.21 88.0 68 H.sup.z C.sub.8 -C.sub.10
hydroxamate 1 0.25 86.5 83 (Soviet Teachings) 0.7 0.71 -- 76 0.9
0.31 -- 77 J H.sup.z + Tall oil fatty (10.5 + 1.5)** 0.20 88.8 44
acid K H.sup.z + decyl alcohol (1.2 + 1.0) 0.17 87.7 62 H.sup.z +
decyl alcohol (0.47 + 0.39) 0.37 89.3 86 H.sup.z + decyl alcohol
(0.7 + 0.58) 0.19 90.0 74 XV C.sub.8 -C.sub.10 hydroxamates of
Example I (0.35 + 0.40)** 0.34 85.0 87 XVI " (0.48 + 0.54) 0.28
85.5 90 XVII " (0.55 + 0.63) 0.24 85.9 86 XVIII " (0.66 + 0.75)
0.30 89.0 90 XIX " (0.88 + 0.10) 0.29 89.5 90
__________________________________________________________________________
*0.77 kg/t of CaCl.sub.2.2H.sub.2 O was added as an activator for
fatty acid flotation of anatase. **First figure represents
hydroxamate dosage; 2nd figure represents decyl alcohol dosage.
***Foaming occurs x & y = products are solid z = anionic
emulsifier used.
The results in Table I demonstrate the superiority of the novel
collectors of the present invention (Examples XV-XIV) over the
fatty acids used commercially (Examples A-D); C.sub.8-10
hydroxamates of the teachings of the Soviet workers (Examples G and
H), and C.sub.8-10 hydroxamates prepared in methanol as in U.S.
Pat. No. 4,629,556 (Examples E and F). With the use of the novel
collector of Example I, the yield of clay is the highest (in the
range 86-90%), and the TiO.sub.2 impurity in the clay product is
low and acceptable (below 0.35%). The brightness of the clay
product is also quite high (85-89.5). It can be readily seen from
these results that with the other collectors all three
requirements-viz. high yield of clay, low TiO.sub.2, and high
brightness-are not simultaneously satisfied at comparable dosages.
In Example F, the metallurgical requirements are satisfied to some
extent (although yield is only 86%), but the dosage of hydroxamate
used (1 kg/T) is too high compared with the hydroxamate dosage of
0.35-0.88 kg/t for the novel collectors of Examples XV-XIX. A
hydroxamate dosage equivalent of about 0.5-0.6 kg/t is shown to be
sufficient for the novel collector of the present invention.
The use of decyl alcohol in conjunction with the C.sub.8-10
hydroxamates prepared according to the Soviet teachings improves
the metallurgy to a slight degree (compare Example H with example
K), but again all three metallurgical requirements are not
concurrently satisfied at comparable dosages thereby indicating
that the hydroxamate prepared by following the Soviet teachings is
inferior.
EXAMPLES XX-XXIV
Following the procedure of Example XIV except that an aged clay is
employed, the following results are obtained.
______________________________________ Dosage % Clay % TiO.sub.2
Example lb/T real* Yield in Clay Brightness
______________________________________ XX 0.58 82.6 0.41 86.3 XXI
0.77 77.3 0.29 87.2 XXII 0.96 75.7 0.28 87.5 XXIII 1.15 75.0 0.28
87.6 XXIV 1.25 71.4 0.29 87.7
______________________________________ *real dosage of hydroxamate
equivalent
EXAMPLES XXV-XXVII
The procedure of Examples XX-XXIV is again followed except that the
composition of Example IV is used and different alcohols are
employed in the hydroxamate production. The results achieved
follow:
______________________________________ Dosage % Clay % TiO.sub.2
Example lb/T real* Yield in Clay Brightness
______________________________________ XXV 1.25 62.9 0.23 87.9
(isooctanol) XXVI 1.25 79.2 0.29 87.4 (Decanol) XXVII 1.25 84.7
0.29 87.7 (Dodecanol) ______________________________________
EXAMPLES XXVIII-XXXII
(Comparative)
Again following the procedure of Examples XX-XXVI except that a
commercially available hydroxamate collector (IM-50) is used, the
following results are observed.
______________________________________ Dosage % Clay % TiO.sub.2
Example lb/T real* Yield in Clay Brightness
______________________________________ XXVIII 0.50 79.2 0.99 84.3
XXIX 0.75 72.1 0.75 85.1 XXX 1.00 76.2 0.57 86.0 XXXI 1.25 72.6
0.42 85.8 XXXII 1.50 71.1 0.37 87.0
______________________________________
EXAMPLES XXXIII-XXXVIII
When the procedure of Example XIV is again followed except that the
collectors of (XXXIII) Example VIII; (XXXIV) Example IX; (XXXV)
Example X; (XXXVI) Example XI; (XXXVII) Example XII and (XXXVIII)
Example XIII are used, similar results are achieved.
* * * * *